Having waterproof safety shoes is essential for all professionals who work outdoors. S3, WRU, or WR standard: which of these standards guarantees the perfect waterproofness of your safety shoes?
S3 Standard
We traditionally distinguish between S1 safety shoes and S3 safety shoes. S3 certified safety shoes meet several standards:
- Anti-perforation midsole (P)
- Antistatic (A)
- Energy absorption in the heel (E)
- Water penetration resistant (WRU) upper leather
- Resistance of the sole to hydrocarbons (FO)
- Lugged outsole.
The WRU standard is thus mandatory in an S3 standard. That is, all S3 certified safety shoes meet the requirements of the WRU standard.
The WRU Standard
The WRU standard is only for the upper of the shoe. It ensures that the upper of the shoe is water repellent. To meet the WRU standard, the material used for the upper is subjected to a test in which the water penetration must not be greater than 0.2 g, and the absorption rate must be less than 30%.
The WR Standard
For waterproofing more excellent than the WRU standard, the WR standard ensures that the shoes are resistant to immersion or, in other words, waterproof. To meet the requirements of the WR standard, safety shoes usually have, in addition to a water-resistant upper, a water-repellent membrane. To be WR certified, a safety shoe is subjected to two tests:
The so-called “bin” test during which the shoes are worn by a person taking 500 steps (which represents approximately 15 min) in 3 cm of water
A dynamic test during which the shoe is placed in a walking simulator and is subjected to 4800 flexions (which represents approximately 80 min) in a basin filled with approximately 7 cm of water.
For a safety sneakers (รองเท้า ผ้าใบ เซฟตี้ which is the term in Thai) to be WR certified, the total penetration surface must not exceed three cm². A WR-certified shoe is therefore not 100% waterproof as the standard tolerates the penetration of liquids.
